1. Field of the Invention
The present invention relates to a semiconductor device having a package which has substantially the same size as that of a semiconductor chip and is particularly suitable for a multiple-output semiconductor chip, as well as a method for manufacturing the same and a method for mounting the same.
2. Description of the Related Art
Conventionally, packages having substantially the same size as semiconductor chips of this type are called a chip-size package, a μ-BGA, a chip-scale package (CSP), and the like, and various types of such packages have been developed. FIG. 24 is a fragmentary perspective view of a semiconductor device having a package of a conventional molded type. This semiconductor device is manufactured by forming bumps 242 on electrode pads of an LSI chip 241, then by resin-encapsulating the LSI chip 241 with a mold resin 243 having substantially the same size as that of the LSI by using a transfer mold, and finally by depositing solder balls 244 on external electrodes.
FIG. 25 shows a cross-sectional view of a semiconductor device having a conventional film (film carrier tape) type. This semiconductor device is manufactured as follows. The surface of an LSI chip 251 is coated with an elastic adhesive (elastomer) 252, a polyimide film 255 on which inner leads 253 and external connection pads 254 have been formed is secured to the surface of the LSI chip 251 by means of the elastic adhesive 252, the inner leads 253 are bonded to the chip electrode pads of the LSI chip 251, and solder balls 256 are deposited on the external connection pads 254.
In addition, FIG. 26 is a cross-sectional view of a semiconductor device having a package of a conventional flip chip bonding type. This semiconductor device is manufactured by forming bumps 262 on the surface of an LSI chip 261, then by effecting face-down bonding the LSI chip 261 on a substrate 263 formed of a ceramic or an organic material, and then by encapsulating the chip by using an encapsulating resin 264. Solder balls 265 are deposited on the reverse surface of the substrate 263. If the package of any one of the types shown in FIGS. 24 to 26 is used, it is possible to manufacture a semiconductor device having a package of substantially the same size as that of the LSI.
However, with the semiconductor device shown in FIG. 24, an exclusive-use transfer mold is required, which has been a factor hampering the effort in lowering the cost of the semiconductor devices.
In addition, with the semiconductor device shown in FIG. 25, since a special elastic adhesive is used between the LSI chip and the tape, the contamination of or the damage to the surface of the LSI chip can occur, possibly deteriorating the reliability. In addition, when the LSI chip and the inner leads are connected, a single bonding method in which the leads are bonded one at a time is used. As a result, in multiple-output packages, the bonding time becomes prolonged, and has constituted a factor hampering the effort in lowering the cost of the semiconductor devices.
Furthermore, with the semiconductor device shown in FIG. 26, the substrate is multilayered in the multiple-output package and is expensive, and in the case of an LSI chip having a large size, the difference in the coefficient of thermal expansion between the substrate and the LSI chip in some cases constitutes a problem in the reliability.